21f831134c
Just enough to consume some bitcode files and link them. There's more to be done around the symbol resolution API and the LTO config, but I don't yet understand what all the various LTO settings do... Reviewed By: #lld-macho, compnerd, smeenai, MaskRay Differential Revision: https://reviews.llvm.org/D90663
83 lines
2.6 KiB
C++
83 lines
2.6 KiB
C++
//===- LTO.cpp ------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "LTO.h"
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#include "Config.h"
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#include "InputFiles.h"
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#include "lld/Common/ErrorHandler.h"
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#include "lld/Common/Strings.h"
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#include "lld/Common/TargetOptionsCommandFlags.h"
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#include "llvm/LTO/LTO.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace lld;
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using namespace lld::macho;
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using namespace llvm;
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static lto::Config createConfig() {
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lto::Config c;
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c.Options = initTargetOptionsFromCodeGenFlags();
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return c;
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}
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BitcodeCompiler::BitcodeCompiler() {
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auto backend =
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lto::createInProcessThinBackend(llvm::heavyweight_hardware_concurrency());
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ltoObj = std::make_unique<lto::LTO>(createConfig(), backend);
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}
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void BitcodeCompiler::add(BitcodeFile &f) {
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ArrayRef<lto::InputFile::Symbol> objSyms = f.obj->symbols();
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std::vector<lto::SymbolResolution> resols;
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resols.reserve(objSyms.size());
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// Provide a resolution to the LTO API for each symbol.
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for (const lto::InputFile::Symbol &objSym : objSyms) {
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resols.emplace_back();
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lto::SymbolResolution &r = resols.back();
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// Ideally we shouldn't check for SF_Undefined but currently IRObjectFile
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// reports two symbols for module ASM defined. Without this check, lld
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// flags an undefined in IR with a definition in ASM as prevailing.
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// Once IRObjectFile is fixed to report only one symbol this hack can
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// be removed.
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r.Prevailing = !objSym.isUndefined();
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// TODO: set the other resolution configs properly
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r.VisibleToRegularObj = true;
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}
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checkError(ltoObj->add(std::move(f.obj), resols));
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}
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// Merge all the bitcode files we have seen, codegen the result
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// and return the resulting ObjectFile(s).
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std::vector<ObjFile *> BitcodeCompiler::compile() {
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unsigned maxTasks = ltoObj->getMaxTasks();
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buf.resize(maxTasks);
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checkError(ltoObj->run([&](size_t task) {
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return std::make_unique<lto::NativeObjectStream>(
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std::make_unique<raw_svector_ostream>(buf[task]));
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}));
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if (config->saveTemps) {
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if (!buf[0].empty())
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saveBuffer(buf[0], config->outputFile + ".lto.o");
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for (unsigned i = 1; i != maxTasks; ++i)
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saveBuffer(buf[i], config->outputFile + Twine(i) + ".lto.o");
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}
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std::vector<ObjFile *> ret;
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for (unsigned i = 0; i != maxTasks; ++i)
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if (!buf[i].empty())
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ret.push_back(make<ObjFile>(MemoryBufferRef(buf[i], "lto.tmp")));
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return ret;
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}
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